How can you tell if plastic is polypropylene?

One of the simplest ways to carry out a flame test is by cutting a sample from the plastic and igniting it in a fume cupboard. The colour of flame, scent and characteristics of burning can give an indication of the type of plastic: 1. Polyethylene (PE) – Drips, smells like candlewax；

2.Polypropylene (PP) – Drips, smells mostly of dirty engine oil and undertones of candlewax；

3. Polymethylmethacrylate (PMMA, “Perspex”) – Bubbles, crackles, sweet aromatic smell；

4. Polyamide or “Nylon” (PA) – Sooty flame, smells of marigolds；

5. Acrylonitrilebutadienestyrene (ABS) – Not transparent, sooty flame, smells of marigolds；

6. Polyethylene foam (PE) – Drips, smells of candlewax